Circuit Sculpture Vibration Sensor

January 10, 2021 by Kristina Panos 15 Comments

Here’s your useful and beautiful circuit for the day — [New Pew]’s vibration sensor takes manual control of the flip-flop inside a 555 timer and lights an LED in response. Use it to detect those vibrations you expect, like laundry machines, or those you only suspect, like the kind that might be coming from your engine. This gadget isn’t super-precise, but it will probably get the job done.

The vibration-detecting bit is a tiny ball bearing soldered to the spring from an old pen, which is tied between the trigger and ground pins of the 555. When the chip is powered with a 9 V battery, nearby vibrations will induce wiggle in the spring, causing the ball bearing to contact the brass rod and completing the circuit. When this happens, the internal flip flop’s output goes high, which turns on the LED. Then the flip flop must be reset with a momentary button. Check out the build video after the break.

Want to pick up Earthly vibrations? You can detect earthquakes with a homemade variable capacitor, a 555, and a Raspberry Pi.

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You Got Something On Your Processor Bus: The Joys Of Hacking ISA And PCI

January 6, 2021 by Maya Posch 32 Comments

Although the ability to expand a home computer with more RAM, storage and other features has been around for as long as home computers exist, it wasn’t until the IBM PC that the concept of a fully open and modular computer system became mainstream. Instead of being limited to a system configuration provided by the manufacturer and a few add-ons that really didn’t integrate well, the concept of expansion cards opened up whole industries as well as a big hobbyist market.

The first IBM PC had five 8-bit expansion slots that were connected directly to the 8088 CPU. With the IBM PC/AT these expansion slots became 16-bit courtesy of the 80286 CPU it was built around. These slots could be used for anything from graphics cards to networking, expanded memory or custom I/O. Though there was no distinct original name for this card edge interface, around the PC/AT era it got referred to as PC bus, as well as AT bus. The name Industry Standard Architecture (ISA) bus is a retronym created by PC clone makers.

With such openness came the ability to relatively easy and cheaply make your own cards for the ISA bus, and the subsequent and equally open PCI bus. To this day this openness allows for a vibrant ecosystem, whether one wishes to build a custom ISA or PCI soundcard, or add USB support to a 1981 IBM PC system.

But what does it take to get started with ISA or PCI expansion cards today? Continue reading “You Got Something On Your Processor Bus: The Joys Of Hacking ISA And PCI” →

Listening To Long Forgotten Voices: An Optical Audio Decoder For 16 Mm Film

January 2, 2021 by Danie Conradie 21 Comments

Like many of us, [Emily] found herself on COVID-19 lockdown over the summer. To make the most of her time in isolation, she put together an optical audio decoder for old 16 mm film, built using modern components and a bit of 3D printing.

It all started with a broken 16 mm projector that [Emily] got from a friend. After repairing and testing the projector with a roll of film bought at a flea market, she discovered that the film contained an audio track that her projector couldn’t play. The audio track is encoded as a translucent strip with varying width, and when a mask with a narrow slit is placed over the top it modulates the amount of light that can pass through to a light sensor connected to speakers via an amplifier.

[Emily] used a pair of razor blades mounted to a 3D printed bracket to create the mask, and a TI OPT101 light sensor together with a light source to decode the optical signal. She tried to use a photoresistor and a discrete photodiode, but neither had the required sensitivity. She built a frame with adjustable positions for an idler pulley and the optical reader unit, an electronics box on one end for the electronic components, and another pulley attached to a stepper motor to cycle a short loop of the film.

Most of the projects we see involving film these days are for creating digital copies. You can digitize your old 35 mm photo film using a Raspberry Pi, some Lego pieces, and a DSLR camera, or do the same for 8 mm film with a 3D printed rig. Continue reading “Listening To Long Forgotten Voices: An Optical Audio Decoder For 16 Mm Film” →

Magic 8-Ball Gets A Modern Makeover

December 23, 2020 by Tom Nardi 13 Comments

Back in 2012, [sjm4306] was surprised when his breadboard rendition of the classic “Magic 8-Ball” popped up on Hackaday. If he had known the project was going to be enshrined on these hallowed pages, he might have tidied things up a bit. Now with nearly a decade of additional electronics experience, he’s back and ready to show off a new and improved version of the project.

The 3D printed case helps sell the look.

Conceptually, not much has changed from the original version. Press a button, get a random response. But on the whole the project is more refined, and not just because it’s moved over to a custom PCB.

The original version used a PIC16F886 with a charge controller and experimental RTC, but this time around [sjm4306] has consolidated all the functionality into the ATmega328P and is powering the whole thing with a simple CR2032 coin cell. As you can see in the video after the break, assembly is about as quick and straight-forward as it gets.

As with the original, there’s no accelerometer onboard. If you want to see a new message from your mystic companion, you’ve got to hold the button to “shake” the ball. A timer counts how long the button is held down, which in turn seeds the pseudorandom number generator that picks the response. Since each person will naturally hold the button for a slightly different amount of time, this keeps things from getting repetitive.

We don’t often see creators revisit their projects from the olden days, but we’d certainly like to. Consider this an open invitation to any hacker who wants to show off how much they’ve refined their skills; do-overs are always welcome here at Hackaday.

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Printed Circuits, 1940s Style

December 8, 2020 by Chris Lott 35 Comments

A presentation this month by the Antique Wireless Museum brought British engineer and inventor John Sargrove (1906-1974) to our attention. If you’ve ever peeked inside old electronics from days gone by, you’ve no doubt seen point-to-point wiring and turret board construction. In the 60s and 70s these techniques eventually made way for printed circuit boards which we still use today. But Mr Sargrove was way ahead of his time, having already invented a process in the 1930s to print circuits, not just boards, onto Bakelite. After being interrupted by the war, he formed a company Electronic Circuit Making Equipment (ECME) and was building broadcast radio receivers on an impressive automatic production line.

Mr. Sargrove’s passion was making radios affordable for everyone. But to achieve this goal, he had to make large advances manufacturing technology. His technique of embedding not only circuit traces, but basic circuit elements like resistors, capacitors, and inductors directly into the substrate foresaw techniques being applied decades later in integrated circuit design. He also developed a compact vacuum tube which could be used in all circuits of a radio, called an “All-stage Valve“. Equally important was his futuristic automatic factory, which significantly reduced the number of factory workers needed to make radios from 1500 to 50. Having completed the radio design, he was also developing a television receiver using the same concepts. Unfortunately, ECME was forced into liquidation when a large order from India was cancelled upon declaration of independence in 1947.

You really must watch the video below. There are many bits and pieces of modern factory automation which we still use today, yet their implementation using 1940s techniques and technology is fascinating. Further reading links after the video. Thanks to [Mark Erdle] for the tip.

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Taking Over The Amazing Control Panel Of A Vintage Video Switcher

November 28, 2020 by Mike Szczys 15 Comments

Where does he get such wonderful toys? [Glenn] snagged parts of a Grass Valley Kalypso 4-M/E video ~~mixer~~ switcher control surface from eBay and since been reverse engineering the button and display modules to bend them to his will. The hardware dates back to the turn of the century and the two modules would have been laid out with up to a few dozen others to complete a video ~~mixing~~ switcher console.

[Glenn’s] previous adventures delved into a strip of ten backlit buttons and gives us a close look at each of the keyswitches and the technique he used to pull together his own pinout and schematic of that strip. But things get a lot hairier this time around. The long strip seen above is a “machine control plane” module and includes a dozen addressible character displays, driven by a combination of microcontrollers and FPGAs. The square panel is a “Crosspoint Switch Matrix” module include eight individual 32 x 32 LCDs drive by three dedicated ICs that can display in red, green, or amber.

[Glen] used an STM8 Nucleo 64 to interface with the panels and wrote a bit of code to help map out what each pin on each machine control plane connector might do. He was able to stream out some packets from the plane that changed as he pressed buttons, and ended up feeding back a brute-force of that packet format to figure out the LED display protocols.

But the LCDs on the crosspoint switch were a more difficult nut to crack. He ended up going back to the original source of the equipment (eBay) to get a working control unit that he could sniff. He laid out a man-in-the-middle board that has a connector on either side with a pin header in the middle for his logic analyzer. As with most LCDs, the secret sauce was the initialization sequence — an almost impossible thing to brute force, yet exceedingly simple to sniff when you have a working system. So far he has them running under USB control, and if you are lucky enough to have some of this gear in your parts box, [Glen] has painstakingly recorded all of the details you need to get them up and running.

C64 Runs On STM32F429 Discovery

November 18, 2020 by Chris Lott 23 Comments

There have been various reincarnations of the Commodore C64 over the years, and [Dave Van Wagner] has created one that can run on an STM32F429ZI Discovery development board. These dev boards have been around quite a few years and feature a 2.4 inch color TFT LCD in addition to the typical I/O circuitry, and are a pretty good value — [Dave] says they currently sell for under $30 through distribution.

The project began earlier this year when [Dave] set out to write a command line program in C# that emulated C64 Basic. He had written a 6502 emulator many years earlier, but had not tested it. [Dave] went on a programming binge in March and got it up and running over a very long weekend. He subsequently decided to add support for VIC-20, TED, and PET as well.

Even though [Dave] says C# is a beautiful language, he subsequently ported the program into C (an ugly language?) in order to run on the Discovery board, swapping the command line terminal interface for real LCD video and a USB keyboard. There’s also an Arduino version (terminal interface only). It runs about 15% slower than a real C64, and there are some limitations still like no SID. But overall, this is a great project and a low-cost way to emulate a C64 in an embedded format. If you want to explore further, here is the Mbed project for the STM32F429, and you can find the Arduino and C# versions on his GitHub page. You may remember [Dave] from the C128 video hack we wrote about last year.